In the last years we have experienced a growing industrial interest in Mobile Cloud Networking (MCN) as the opportunity to exploit the cloud computing paradigm through Network Function Virtualization (NFV), primarily with the goal to reduce CAPEX/OPEX for future mobile networks deployment and operation. The gain from the point of view of infrastructure costs reduction is almost clear and recognized, while many technical challenges are still to be solved, especially with industry-mature solutions, due to the complexity of managing such type of infrastructures. In particular, the dynamicity and flexibility introduced by the virtualization of network functions add novel requirements on the service management and orchestration layers. In this perspective, this paper originally presents the architecture and primary implementation guidelines of the Mobile Cloud Networking framework developed within a large EU FP7 project. More specifically, it focuses on the innovative technical elements of our solution for service management and orchestration, namely i) orchestration strategies based on resource unit affinity and ii) compliance with emerging Open Cloud Computing Interface (OCCI) standards. To practically demonstrate the suitability of the proposed approach, a specific real use case has been implemented, i.e., the cloudification of the 3GPP IP Multimedia Subsystem (IMS), by reporting and analyzing the related performance results.